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Mycological Research News1
Mycol. Res. 104 (9) : 1025–1026 (September 2000). Printed in the United Kingdom.
1025
Mycological Research News1
This month Mycological Research News features work on chromosome translocations in six closely related Saccharomyces species, and analyses of the largest rDNA data sets of fungi yet published which call into question some proposed phylogenies and natural groupings. Amongst the 16 papers in this issue are molecular studies exploring the diversity of soil fungi, rDNA and taxonomy of Ganoderma, RAPD analyses of Armillaria mellea populations, relationships of Phytophthora species, variation in P. cactorum, dsRNA viruses in Metarhizium anisopliae isolates, the genetic structure of Cryphonectria parasitica populations, and the array of Trichoderma isolates from Russia, Siberia and Himalaya. The effects of mycorrhizal and non-mycorrhizal root exudates on the sporulation of Phytophthora fragariae are reported, and the cytology and ultrastructure of Fusarium culmorum and Mycosphaerella graminicola on wheat are documented. The fruiting inducing factor from Phellinus contiguus has been partially characterized, and the resistance of Acer pseudoplatanus wood to Armillaria mellea degradation is explored. The distribution of fungi on fallen Pinus sylvestris needles is examined along altitudinal transects, and a remarkable diversity of fungi on Picea abies documented. Craspedodidymum nigroseptatum sp. nov. is described and a key to the species provided.
IN THIS ISSUE How to assess the diversity of fungi in soil is one of the longstanding problems of fungal ecology. A promising cultureindependent approach based on the direct amplification of RFLPs of ITS rDNA sequences is described and compared with cultures obtained (pp. 1027–1032). The characterization of Ganoderma species is one of the most challenging tasks facing mycologists, as evidenced by the studies of Australian isolates reported in the August issue of Mycological Research using ITS rDNA sequences (pp. 943–951) and isozymes (pp. 952–961). This month, a range of molecular approaches to the South American species are reported which show a good agreement with morphological data at the subegeneric level but leave questions at the specific level (pp. 1033–1045). Major advances have been made in recent years in our understanding of Armillaria species (cfr p. 896 in the July issue), but studies of incompatibility and RAPD DNA analyses of A. mellea s. str. heterothallic and nonheterothallic populations reveal four somatic incompatability groups and three RAPD groups (pp. 1046–1054). In the case of another taxonomically difficult genus, Trichoderma, much also remains to be resolved ; of 75 isolates from Russia, Siberia and Himalaya examined by molecular methods, 26 belonged
" Mycological Research News is compiled by David L. Hawksworth, Executive Editor Mycological Research, MycoNova, 114 Finchley Lane, Hendon, London NW4 1DG, UK (tel.\fax : [j44] (0)20 8203 4282 ; e-mail : myconova!btinternet.com), to whom suggestions for inclusion and short items for consideration should be submitted. Unsigned items are by the Executive Editor.
to six groups similar to but different from currently known species (pp. 1117–1125). Three papers in this issue concern Phytophthora species. The variation in the genus based on ITS1 DNA sequences demonstrates that morphological characters traditionally used in the genus are of limited value in deducing phylogenetic relationships (pp. 1055–1061). Analyses of randomly amplified microsatellite markers (RAMS) in P. cactorum establish that leather- and crown- rots of strawberries are not caused by different strains, but that differences exist between North American and European populations (pp. 1062–1068). Sporulation in P. fragariae, however, is stimulated more by exudates of non-mycorrhizal than mycorrhizal roots of strawberry (pp. 1069–1073). The cytology and ultrastructure of infections by two wheat pathogens, Fusarium culmorum (pp. 1083–1093) and Mycosphaerella graminicola, (pp. 1074–1082) are documented in detail using a wide range of microscopic techniques. Vegetative incompatability and DNA fingerprinting has proved of value in determining the origins and spread of another pathogen, Cryphonectria parasitica, in newly established Swiss populations of this fungus (pp. 1108–1116). Homologous dsRNA viruses in the entomopathogenic Metarhizium anisopliae occur in related isolates and appear to be horizontally transferred and maintained through clonal lineages, and similarly sized viruses are not always homologous (pp. 1094–1097). Continuing studies of fruiting in Phellinus contiguus have led to a partial characterization of the fruiting-inducing factor using a variety of chemical approaches (pp. 1098–1107). Wood-rotting by Armillaria mellea on sycamore (Acer
1025
Mycological Research News1
This month Mycological Research News features work on chromosome translocations in six closely related Saccharomyces species, and analyses of the largest rDNA data sets of fungi yet published which call into question some proposed phylogenies and natural groupings. Amongst the 16 papers in this issue are molecular studies exploring the diversity of soil fungi, rDNA and taxonomy of Ganoderma, RAPD analyses of Armillaria mellea populations, relationships of Phytophthora species, variation in P. cactorum, dsRNA viruses in Metarhizium anisopliae isolates, the genetic structure of Cryphonectria parasitica populations, and the array of Trichoderma isolates from Russia, Siberia and Himalaya. The effects of mycorrhizal and non-mycorrhizal root exudates on the sporulation of Phytophthora fragariae are reported, and the cytology and ultrastructure of Fusarium culmorum and Mycosphaerella graminicola on wheat are documented. The fruiting inducing factor from Phellinus contiguus has been partially characterized, and the resistance of Acer pseudoplatanus wood to Armillaria mellea degradation is explored. The distribution of fungi on fallen Pinus sylvestris needles is examined along altitudinal transects, and a remarkable diversity of fungi on Picea abies documented. Craspedodidymum nigroseptatum sp. nov. is described and a key to the species provided.
IN THIS ISSUE How to assess the diversity of fungi in soil is one of the longstanding problems of fungal ecology. A promising cultureindependent approach based on the direct amplification of RFLPs of ITS rDNA sequences is described and compared with cultures obtained (pp. 1027–1032). The characterization of Ganoderma species is one of the most challenging tasks facing mycologists, as evidenced by the studies of Australian isolates reported in the August issue of Mycological Research using ITS rDNA sequences (pp. 943–951) and isozymes (pp. 952–961). This month, a range of molecular approaches to the South American species are reported which show a good agreement with morphological data at the subegeneric level but leave questions at the specific level (pp. 1033–1045). Major advances have been made in recent years in our understanding of Armillaria species (cfr p. 896 in the July issue), but studies of incompatibility and RAPD DNA analyses of A. mellea s. str. heterothallic and nonheterothallic populations reveal four somatic incompatability groups and three RAPD groups (pp. 1046–1054). In the case of another taxonomically difficult genus, Trichoderma, much also remains to be resolved ; of 75 isolates from Russia, Siberia and Himalaya examined by molecular methods, 26 belonged
" Mycological Research News is compiled by David L. Hawksworth, Executive Editor Mycological Research, MycoNova, 114 Finchley Lane, Hendon, London NW4 1DG, UK (tel.\fax : [j44] (0)20 8203 4282 ; e-mail : myconova!btinternet.com), to whom suggestions for inclusion and short items for consideration should be submitted. Unsigned items are by the Executive Editor.
to six groups similar to but different from currently known species (pp. 1117–1125). Three papers in this issue concern Phytophthora species. The variation in the genus based on ITS1 DNA sequences demonstrates that morphological characters traditionally used in the genus are of limited value in deducing phylogenetic relationships (pp. 1055–1061). Analyses of randomly amplified microsatellite markers (RAMS) in P. cactorum establish that leather- and crown- rots of strawberries are not caused by different strains, but that differences exist between North American and European populations (pp. 1062–1068). Sporulation in P. fragariae, however, is stimulated more by exudates of non-mycorrhizal than mycorrhizal roots of strawberry (pp. 1069–1073). The cytology and ultrastructure of infections by two wheat pathogens, Fusarium culmorum (pp. 1083–1093) and Mycosphaerella graminicola, (pp. 1074–1082) are documented in detail using a wide range of microscopic techniques. Vegetative incompatability and DNA fingerprinting has proved of value in determining the origins and spread of another pathogen, Cryphonectria parasitica, in newly established Swiss populations of this fungus (pp. 1108–1116). Homologous dsRNA viruses in the entomopathogenic Metarhizium anisopliae occur in related isolates and appear to be horizontally transferred and maintained through clonal lineages, and similarly sized viruses are not always homologous (pp. 1094–1097). Continuing studies of fruiting in Phellinus contiguus have led to a partial characterization of the fruiting-inducing factor using a variety of chemical approaches (pp. 1098–1107). Wood-rotting by Armillaria mellea on sycamore (Acer